A top adviser to former Massachusetts governor Mitt Romney appears to be behind the launch of a new Web site attacking GOP presidential rival Fred D. Thompson during his first week on the trail.

The site, PhoneyFred.org, painted an unflattering picture of Thompson, dubbing the former TV star and senator Fancy Fred, Five O’clock Fred, Flip-Flop Fred, McCain Fred, Moron Fred, Playboy Fred, Pro-Choice Fred, Son-of-a-Fred and Trial Lawyer Fred. Shortly after a Washington Post reporter made inquiries about the site to the Romney campaign, it was taken down.

Before it vanished, the front page of the Web site featured a picture of Thompson depicted in a frilly outfit more befitting a Gilbert and Sullivan production than a presidential candidate.

Under the heading “Playboy Fred,” the site asked the provocative question: “Once a Pro-Choice Skirt Chaser, Now Standard Bearer of the Religious Right?”

Nowhere on the site was any indication of who was responsible for it. But a series of inquiries led to “Under the Power Lines,” the Web site of the political consulting firm of J. Warren Tompkins, Romney’s lead consultant in South Carolina. Tompkins did not return phone calls seeking comment.